Wikipedia says “A blog (a contraction of the term “Web log”) is a Web site, usually maintained by an individual with regular entries of commentary, descriptions of events, or other material such as graphics or video.”
Basically, a blog is an online journal. You can write or post about whatever you like: updates of your life, political opinions, a great trip, favorite recipes, what music you’re listening to — anything that strikes your fancy.
Many blogs provide commentary or news on a particular subject; others function as more personal online diaries. A typical blog combines text, images, and links to other blogs, Web pages, and other media related to its topic. The ability for readers to leave comments in an interactive format is an important part of many blogs.
Further Reading
Yahoo 360
Wordpress
Blogger
